Hi Mez,
I have just read you posting.
Similar thing happened too me also. Without going into detail. We didn't haven't the fertilisation rate that was expected, very low considering how great our EPU and DH's sample was. Anyway the short and the long - we waited until the shock had passed and then we went in and had a very long chat to our specialist. He was very good and basically gave us a fantastic anatomy lesson and we better understand what "could" have possibly been the issue in our case. It has really empowered us to make future decisions on where we go and what we do.
So I guess that's the only thing I can suggest.....let the shock subside and then go and see your specialists. Go armed with lots of questions and then (like me) write down your answers.
Good luck
Deb